Magnetic separator flow control



Jan. 3, 1967 H. L. GENIER 3,295,678

MAGNETIC SEPARATOR FLOW CONTROL Filed July 19, 1962 4 Sheets-Sheet lINVENTOR.

HEN/F) L. 6E/V/7? Jan. 3, 1967 H- L. GENIER MAGNETIC SEPARATOR FLOWCONTROL 4 Sheets-Sheet 2 Filed July 19, 1962 hm. wm

INVENTOR. HEN/FY GEN/EA AT T ORNEYS'.

Jan. 3, 1967 H- GENIER MAGNETIC SEPARATOR FLOW CONTROL 4 Sheets-Sheet 3Filed July 19, 1962 ull INVENTOR HEN/Pr L. GfW/ff? ATTU/ENEKS'.

Jan. 3, 1967 H. GENIER MAGNETIC SEPARATOR FLOW CONTROL 4 Sheets-Sheet 4Filed July 19, 1962 INVENTOR. HE/V/P) L. GEN/[R QWPFM ATTOENEYZ UnitedStates Patent 3,295,678 MAGNETIC SEPARATOR FLOW CONTROL Henry L. Genier,Silver Bay, Minn., assignor to Reserve Mining Company, Silver Bay,Minn., a corporation of IVIinnesota Filed July 19, 1962, Ser. No.210,976 1 Claim. (Cl. 209-223) The present invention relates to magneticseparators which are used for separating magnetizable material from acommingled slurry containing also non-magnetizable fractions normallytermed gangue, tailings, or the like. The finely ground material, mixedwith water, is fed past one or more magnets developing a fairly densemagnetic field whereupon the magnetic portion of the slurry is attractedtowards the magnets and the nonmagnetic material or tailings passes to aplace of disposal.

The apparatus just mentioned may be one of several embodiments but willbe herein shown and described as a drum separator assembly wherein oneor more magnets are disposed within and adjacent to one wall portion ofthe drum, and the slurry flows past the drum, contacting said wallportion as it passes. The magnetizable fraction adheres to the drum walland is carried out of the magnetic field by drum rotation, whereupon itdrops off the drum and proceeds further, possibly to additionalseparating and concentrating means. A number of such drums may be usedin tandem, the slurry flowing past each drum in sequence, losing moreand more of the tailings as it progresses, and consequently becomingmore and more concentrated in percentage of ferrous metal.

There are other types of magnetic separators, such as the so-called belttype wherein the magnets are disposed behind an endless travelling beltbut for simplicity the invention is described herein as adaptable to thedrum type separator.

An object of the present invention is to provide novel and improvedmeans for more effi-ciently directing the ore slurry to the field of themagnetic separator.

A further object of the invention is to provide improved restrictedchannel means through which the slurry must pass, said channel beingimmediately adjacent to the drum surface.

A further object of the invention is to provide, in the aforesaidrestricted channel, adjustable weir means whereby the cross sectionalarea of the fluid carrying channel can be varied to compensate for othervariables such as slurry stream velocity or slurry density.

A further object of the invention is to provide weir means as defined inthe last preceding paragraph wherein the adjustable part of the weir isformed from flexible material to prevent jamming or entrapment ofoversized pieces of ore or tramp metal between the weir and the drum,and consequent scoring of the drum surface.

Other objects and advantages will be apparent from a study of thefollowing description of one embodiment of the invention, in conjunctionwith the accompanying drawings, in which:

FIG. 1 is a top plan View of a three-drum magnetic separator embodyingmy invention.

FIGS. 2 and 3 are sectional views taken respectively on the lines 2--2and 3-3 of FIG. 1.

FIGS. 4 and 5 are perspective views showing details of weirs,partitions, et-c., within the magnetic separator housing.

FIG. 6 is an enlarged sectional detail of one of the adjustablepartitions, shown in smaller scale in FIG. 2.

Speaking first generally, with reference especially to FIGS. 1 and 2, Ishow a bank of magnetic separators assembled in tandem in a steppedtri-level housing, there being successive drums 20, 21 and 22, one toeach level,

to constitute three separating units. The gradation in level facilitatesgravity flow of the slurry. Since the three units are similar, adescription of one will suflice.

The drum 20 is rotated by means of a motor 23 through a chain or belt24, the motor being carried on an adjustable frame 25 on an uprightbracket 26 carried on the separator side wall 27. The frame is pivotallycarried on the pin 28, and chain tension is maintained by means of theadjustable bolt 29.

The drum rotates on a fixed shaft 32 journalled in opposed bearings 33and 34 (FIG. 1) on the housing side walls.

Within the drum 20 is a cluster of magnets 35 carried in a frame 36fixed on shaft 32 so that they maintain their position relative to thelevel of the slurry in which the drum is partially immersed. The magnetscan be of the permanent type, made from Alnico or the like, or theycould be electro-magnets. As a result of this construction, magneticmaterial in the slurry flowing past the lower portion of the drum (FIG.2) will be attracted towards the drum periphery, and will adhere to saidperiphery until it passes out of the magnetic field established by themagnets.

The path of flow of the slurry which may contain a magnetic ferrousmetal ore such as taconite will now be outlined. It enters an inletfitting 37 in the top of a receiving trough 38 which has a side opening39 to determine the level at which the slurry flows from trough 38 intoa first chamber 40. In this chamber the slurry is agitated and renderedrelatively homogeneous by means of water jets directed upwardly throughopenings 41 in a cross pipe 42 which is in communication with a supplymain 43.

When the slurry in chamber 40 reaches the level of the top edge of aweir portion 46, later to be more fully described, it flows over saidedge into a second chamber 47. In passing from chamber 40 across theweir into chamber 47 the slurry flows through a strong magnetic fieldgenerated by magnets 35, and a substantial fraction of the magneticmaterial adheres to the drum surface and is carried over weirs 48 and 49after which it leaves the magnetic field and drops into a third chamber50.

Returning briefly to chamber 47, the non-magnetic portion of the slurrytends to drop towards the bottom of the chamber, Where a substantialportion leaves through outlet 55. The amount of slurry, mostlynonmagnetic, leaving outlet 55 is less than the amount entering overweir 46, so that flow continues over weir 48. A valve control (notshown) can be supplied for outlet 55 to maintain any desired equilibriumbetween the slurry entering from trough 38, the water entering from pipe42, and the slurry leaving over weir 48. The inclined partition 4%defines a chamber 53 (FIG. 2) which retains magnetic particlesaccidentally dropped from the drum surface, and turbulence thereindirects them back into the magnetic field.

In like manner the slurry passes in succession through chambers 56, 57,and 58, over successive weir portions 59, 60, 61, 62, 63 and 64. Fromthe previous description of what occurs at drum 20, it will beunderstood that additional gangue or tailing is removed at outlets 67and 68, and that the remaining slurry becomes more enriched in magneticmaterial as it passes each of the drums 21 and 22, and passes over thelast weir 64 into a receptacle 66 from whence it is directed to furtherseparating apparatus and/0r processes, or to a filter for removal ofexcess water.

FIGS. 4 and 5 show more clearly, in perspective, the wall arrangementwhich bounds chamber 47. The adjustable portions 46, 48 and 49 along thetop edges of the transverse partitions (FIG. 2) are not shown in FIGURES4 and 5, but the respective supporting partitions themselves are shown,being designated respectively 46a, 48a and 49a and these in turn arefixed at the.

respective tops of walls 46b, 43b and 49b. The inset side wall parts 69and 70 lie closely adjacent to the drum end walls to confine slurry flowto the channel immediately adjacent to the cylindrical operating surfaceof the drum. The outer walls 71 and 72 have respective overflow slots 73and 74 to maintain the slurry at the predetermined optimum workinglevel.

Systems generally similar to those just described have heretofore beenknown. In the operation of such a system it sometimes happens that anoversized piece of hard ore, or a piece of tramp metal such as afragment of a rod from a rod mill, was carried along with the slurry andjammed in the channel slot between the top of a partition (such as 48ain FIG. 5) and the rotating drum, badly scoring the drum surface orforcibly stopping drum rotation. The scoring may be deep enough topuncture the cover, whereupon slurry enters the drum and shorts out themagnetic field. A channel slot of fixed height does not accommodateproperly to varying rates of flow or densities of slurry so as to yieldpredictable results.

I have found that both of the disadvantages mentioned in the lastpreceding paragraph are avoided by supplying adjustable edge or Weirportions 46, 48, 49, 60, 61, 62, 63, 64 along the top edge of the fixedweir partitions 46a, 48a, etc. The structure is best seen in section inFIG. 6 wherein the fixed weir edge part 49a carries the resilient strip49. The strip is slotted at 77 to permit upward and downward movement onthe bolt shank 78. The belt clamps the strip 49 (which is doubled inthickness at the upper portion) between part 4% and the washer 79.

When using a Weir of this type oversized pieces of material or trampmetal will not jam in the slots indicated by the arrows A because theresilient strip yields, and does not afford suflicient backing to resultin scoring of the drum. The resilient weir edge parts 46, 48, etc., canbe raised or lowered to any desired position to regulate the rate offlow. FIG. 3 shows side passages 80 for carrying away excess overflowliquid which leaves the housing by control slots such as 73.

The injection of water jets sets up turbulence in compension so that allsolid matter is directed past and through the effective part of themagnetic field.

What is claimed is:

Apparatus for the removal of a magnetically separatable fraction from aslurry of commingled ferrous metal ore and non-magnetic tailings, saidapparatus comprising an enclosure, a compartment in said enclosure,means for directing a stream of said slurry through said compartment,means for maintaining a liquid level in said compartment, meansproviding a surface movable through said stream with one side thereof incontact with said stream, means for establishing a magnetic fieldclosely adjacent to said surface on the opposite side of said surfacefrom said stream whereby magnetic material entrained in said stream isattracted towards said surface, unidirectional flow through saidcompartment being maintained with respect to said magneticallyseparatable fraction and said non-magnetic tailings and said liquid,means for confining said stream to a zone adjacent said opposite side ofsaid surface, said last named means including a weir for controlling thefluid and solids passage capacity of said zone, and means carried bysaid weir to automatically permit passage of oversized solids betweensaid weir and said surface whereby to prevent scoring of said surface.

References Cited by the Examiner UNITED STATES PATENTS 2,426,352 8/1947Johnson 209 332 2,627,976 2/1953 Stearns 209-223 2,698,685 1/1955 Newton209 233 FOREIGN PATENTS 531,814 10/1956 Canada. 732,229 2/1943 Germany.

416,534 9/1934 Great Britain.

HARRY B. THORNTON, Primary Examiner.

R. HALPER, Assistant Examiner,

